1. Field of the Invention
The present invention relates to an electrochromic display device (hereinafter referred to simply as "ECD") having many display segments. More particularly, the present invention relates to ECD having a number of display segments in the form of dots.
2. Discussion of Background
ECD has merits such as excellent memory characteristics and good contrast in the display, and accordingly has been desired to be employed for various display devices. However, as compared with a liquid crystal display device (hereinafter referred to simply as "LCD"), a great electric current flows instantaneously at the time of driving, and it is necessary to minimize the resistance of the leads connected to the respective segments. As opposed to LCD, multiplexing drive is not applicable, and it is required to form one lead for every segment. Accordingly, if the number of segments is increased, the pattern design becomes difficult, and the leads are obliged to be slender and be put around for a increased lead length, whereby the resistance increases, and the response speed of ECD tends to decrease.
On the other hand, in ECD, LCD, etc., it has been known to form leads by lamination of electro conductive layers, or to lead out the segments through through-holes to the rear side of a substrate. However, the lamination of electro conductive layers leads to poor productivity, and is hardly applicable particularly in the case where a number of segments are to be provided as in the case of a dot matrix display. In the case of providing through-holes, an electrode formed on one side of a substrate is led out through the substrate to the other side of the substrate. Such a method is not useful for ECD, since it is not practical to lead out a display electrode formed on the rear side of a display substrate through the substrate to the front side of the substrate.